According to the Mayo Clinic, unspecified essential hypertension means the doctor does not know the root cause of the high blood pressure. This type of hypertension tends to develop gradually over many years. Doctors also refer to this type of high blood pressure as primary hypertension.
The New York Times health guide explains that many factors affect the blood pressure, including the levels of different body hormones and the amount of water and salt in the body. The overall condition of the kidneys, nervous system or blood vessels also comes into play. WebMD notes various symptoms of hypertension, including blood in the urine, chest pain, difficulty breathing, fatigue or confusion, irregular heartbeat, severe headaches and vision problems. It also cites pounding in the chest, neck or ears as a symptom.
The Mayo Clinic further explains that people who have secondary hypertension have an underlying condition causing the hypertension. However, secondary hypertension tends to appear suddenly and causes higher blood pressure than does primary hypertension.
Root causes of secondary hypertension include adrenal gland tumors, alcohol abuse, congenital defects in blood vessels, use of stimulant drugs, kidney problems, obstructive sleep apnea and thyroid problems. Medications such as birth control pills, cold remedies, decongestants, over-the-counter pain relievers and some prescription drugs also sometimes cause problems with blood pressure.